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Author |
Afonso, V.I.; Olmo, G.J.; Orazi, E.; Rubiera-Garcia, D. |
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Title |
New scalar compact objects in Ricci-based gravity theories |
Type |
Journal Article |
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Year |
2019 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
12 |
Issue |
12 |
Pages |
044 - 20pp |
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Keywords |
modified gravity; gravity; GR black holes; Wormholes |
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Abstract |
Taking advantage of a previously developed method, which allows to map solutions of General Relativity into a broad family of theories of gravity based on the Ricci tensor (Ricci-based gravities), we find new exact analytical scalar field solutions by mapping the free-field static, spherically symmetric solution of General Relativity (GR) into quadratic f(R) gravity and the Eddington-inspired Born-Infeld gravity. The obtained solutions have some distinctive feature below the would-be Schwarzschild radius of a configuration with the same mass, though in this case no horizon is present. The compact objects found include wormholes, compact balls, shells of energy with no interior, and a new kind of object which acts as a kind of wormhole membrane. The latter object has Euclidean topology but connects antipodal points of its surface by transferring particles and null rays across its interior in virtually zero affine time. We point out the relevance of these results regarding the existence of compact scalar field objects beyond General Relativity that may effectively act as black hole mimickers. |
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Address |
[Afonso, Victor I.] Univ Fed Campina Grande, Unidade Acad Fis, BR-58429900 Campina Grande, PB, Brazil, Email: viafonso@df.ufcg.edu.br; |
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Publisher |
Iop Publishing Ltd |
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English |
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ISSN |
1475-7516 |
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Conference |
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Notes |
WOS:000507261900041 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4252 |
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Permanent link to this record |
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Author |
Afonso, V.I.; Olmo, G.J.; Orazi, E.; Rubiera-Garcia, D. |
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Title |
Correspondence between modified gravity and general relativity with scalar fields |
Type |
Journal Article |
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Year |
2019 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
99 |
Issue |
4 |
Pages |
044040 - 15pp |
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Keywords |
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Abstract |
We describe a novel procedure to map the field equations of nonlinear Ricci-based metric-affine theories of gravity, coupled to scalar matter described by a given Lagrangian, into the field equations of general relativity coupled to a different scalar field Lagrangian. Our analysis considers examples with a single and N real scalar fields, described either by canonical Lagrangians or by generalized functions of the kinetic and potential terms. In particular, we consider several explicit examples involving foRthorn theories and the Eddington-inspired Born-Infeld gravity model, coupled to different scalar field Lagrangians. We show how the nonlinearities of the gravitational sector of these theories can be traded to nonlinearities in the matter fields and how the procedure allows to find new solutions on both sides of the correspondence. The potential of this procedure for applications of scalar field models in astrophysical and cosmological scenarios is highlighted. |
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Address |
[Afonso, Victor, I] Univ Fed Campina Grande, Unidade Acad Fis, BR-58429900 Campina Grande, Paraiba, Brazil, Email: viafonso@df.ufcg.cdu.br; |
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Amer Physical Soc |
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English |
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ISSN |
2470-0010 |
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Expedition |
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Conference |
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Notes |
WOS:000459210600012 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3914 |
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Author |
Afonso, V.I.; Olmo, G.J.; Orazi, E.; Rubiera-Garcia, D. |
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Title |
Mapping nonlinear gravity into General Relativity with nonlinear electrodynamics |
Type |
Journal Article |
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Year |
2018 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
78 |
Issue |
10 |
Pages |
866 - 11pp |
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Keywords |
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Abstract |
We show that families of nonlinear gravity theories formulated in a metric-affine approach and coupled to a nonlinear theory of electrodynamics can be mapped into general relativity (GR) coupled to another nonlinear theory of electrodynamics. This allows to generate solutions of the former from those of the latter using purely algebraic transformations. This correspondence is explicitly illustrated with the Eddington-inspired Born-Infeld theory of gravity, for which we consider a family of nonlinear electrodynamics and show that, under the map, preserve their algebraic structure. For the particular case of Maxwell electrodynamics coupled to Born-Infeld gravity we find, via this correspondence, a Born-Infeld-type nonlinear electrodynamics on the GR side. Solving the spherically symmetric electrovacuum case for the latter, we show how the map provides directly the right solutions for the former. This procedure opens a new door to explore astrophysical and cosmological scenarios in nonlinear gravity theories by exploiting the full power of the analytical and numerical methods developed within the framework of GR. |
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Address |
[Afonso, Victor I.] Univ Fed Campina Grande, Unidade Acad Fis, BR-58429900 Campina Grande, PB, Brazil, Email: viafonso@df.ufcg.edu.br; |
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Springer |
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English |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6044 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000448428400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3776 |
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Permanent link to this record |
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Author |
Afonso, V.I.; Olmo, G.J.; Rubiera-Garcia, D. |
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Title |
Mapping Ricci-based theories of gravity Into general relativity |
Type |
Journal Article |
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Year |
2018 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
97 |
Issue |
2 |
Pages |
021503 - 6pp |
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Keywords |
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Abstract |
We show that the space of solutions of a wide class of Ricci-based metric-affine theories of gravity can be put into correspondence with the space of solutions of general relativity (GR). This allows us to use well-established methods and results from GR to explore new gravitational physics beyond it. |
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Address |
[Afonso, V. I.] Univ Fed Campina Grande, Unidade Acad Fis, BR-58109970 Campina Grande, PB, Brazil, Email: viafonso@df.ufcg.edu.br; |
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Publisher |
Amer Physical Soc |
Place of Publication |
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English |
Summary Language |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2470-0010 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000423656900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3467 |
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Permanent link to this record |
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Author |
Afonso, V.I.; Olmo, G.J.; Rubiera-Garcia, D. |
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Title |
Scalar geons in Born-Infeld gravity |
Type |
Journal Article |
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Year |
2017 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
08 |
Issue |
8 |
Pages |
031 - 35pp |
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Keywords |
modified gravity; Wormholes |
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Abstract |
The existence of static, spherically symmetric, self-gravitating scalar field solutions in the context of Born-Infeld gravity is explored. Upon a combination of analytical approximations and numerical methods, the equations for a free scalar field (without a potential term) are solved, verifying that the solutions recover the predictions of General Relativity far from the center but finding important new effects in the central regions. We find two classes of objects depending on the ratio between the Schwarzschild radius and a length scale associated to the Born-Infeld theory: massive solutions have a wormhole structure, with their throat at r = 2 M, while for the lighter configurations the topology is Euclidean. The total energy density of these solutions exhibits a solitonic profile with a maximum peaked away from the center, and located at the throat whenever a wormhole exists. The geodesic structure and curvature invariants are analyzed for the various configurations considered. |
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Address |
[Afonso, V. I.] Univ Fed Campina Grande, Unidade Acad Fis, BR-58109970 Campina Grande, PB, Brazil, Email: viafonso@df.ufcg.edu.br; |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1475-7516 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000408311900031 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3285 |
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Permanent link to this record |
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Author |
Agaras, M.N. et al; Fiorini, L. |
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Title |
Laser calibration of the ATLAS Tile Calorimeter during LHC Run 2 |
Type |
Journal Article |
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Year |
2023 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
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Volume |
18 |
Issue |
6 |
Pages |
P06023 - 35pp |
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Keywords |
Calorimeter methods; Photon detectors for UV; visible and IR photons (vacuum) (photomultipliers; HPDs; others); Calorimeters; Scintillators; scintillation and light emission processes (solid; gas and liquid scintillators) |
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Abstract |
This article reports the laser calibration of the hadronic Tile Calorimeter of the ATLAS experiment in the LHC Run 2 data campaign. The upgraded Laser II calibration system is described. The system was commissioned during the first LHC Long Shutdown, exhibiting a stability better than 0.8% for the laser light monitoring. The methods employed to derive the detector calibration factors with data from the laser calibration runs are also detailed. These allowed to correct for the response fluctuations of the 9852 photomultiplier tubes of the Tile Calorimeter with a total uncertainty of 0.5% plus a luminosity-dependent sub-dominant term. Finally, we report the regular monitoring and performance studies using laser events in both standalone runs and during proton collisions. These studies include channel timing and quality inspection, and photomultiplier linearity and response dependence on anode current. |
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Address |
[Agaras, M. N.] Barcelona Inst Sci & Technol, Inst Fis Altes Energies IFAE, Barcelona, Spain, Email: rute.pedro@cern.ch |
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Publisher |
IOP Publishing Ltd |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-0221 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001108200700004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5970 |
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Permanent link to this record |
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Author |
Agarwalla, S.K.; Masud, M. |
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Title |
Can Lorentz invariance violation affect the sensitivity of deep underground neutrino experiment? |
Type |
Journal Article |
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Year |
2020 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
80 |
Issue |
8 |
Pages |
716 - 18pp |
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Keywords |
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Abstract |
We examine the impact of Lorentz Invariance Violation (LIV) in measuring the octant of theta(23) and CP phases in the context of the Deep Underground Neutrino Experiment (DUNE). We consider the CPT-violating LIV parameters involving e-mu(a(e mu)) and e-tau (a(e tau)) flavors, which induce an additional interference term in neutrino and antineutrino appearance probabilities. This newinterference term depends on both the standard CP phase delta and the new dynamical CP phase phi(e mu)/phi(e tau), giving rise to new degeneracies among (theta(23), delta, phi). Taking one LIV parameter at-a-time and considering a small value of vertical bar a(e mu)vertical bar = vertical bar a(e tau)vertical bar = 5 x 10(-24) GeV, we find that the octant discovery potential of DUNE gets substantially deteriorated for unfavorable combinations of delta and phi(e mu)/phi(e tau). The octant of theta(23) can only be resolved at 3 sigma if the true value of sin(2) theta(23) less than or similar to 0.42 or >= 0.62 for any choices of delta and phi. Interestingly, we also observe that when both the LIV parameters a(e mu) and a(e tau) are present together, they cancel out the impact of each other to a significant extent, allowing DUNE to largely regain its octant resolution capability. We also reconstruct the CP phases delta and phi(e mu)/phi(e tau). The typical 1 sigma uncertainty on delta is 10-15 degrees. and the same on phi(e mu)/phi(e tau) is 25-30 degrees depending on the choices of their true values. |
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Address |
[Agarwalla, Sanjib Kumar; Masud, Mehedi] Inst Phys, Sachivalaya Marg, Bhubaneswar 751005, India, Email: sanjib@iopb.res.in; |
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Publisher |
Springer |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6044 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000557368800001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4493 |
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Permanent link to this record |
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Author |
AGATA Collaboration (Avigo, R. et al); Domingo-Pardo, C.; Gadea, A.; Gonzalez, V. |
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Title |
Low-lying electric dipole gamma-continuum for the unstable Fe-62(,)64 nuclei: Strength evolution with neutron number |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
811 |
Issue |
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Pages |
135951 - 6pp |
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Keywords |
Fe-64; Fe-62; Nuclear structure; Dipole excitation around neutron threshold |
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Abstract |
The gamma-ray emission from the nuclei Fe-62,Fe-64 following Coulomb excitation at bombarding energy of 400-440 AMeV was measured with special focus on E1 transitions in the energy region 4-8 MeV. The unstable neutron-rich nuclei Fe-62,Fe-64 were produced at the FAIR-GSI laboratories and selected with the FRS spectrometer. The gamma decay was detected with AGATA. From the measured gamma-ray spectra the summed E1 strength is extracted and compared to microscopic quasi-particle phonon model calculations. The trend of the E1 strength with increasing neutron number is found to be fairly well reproduced with calculations that assume a rather complex structure of the 1(-) states (three-phonon states) inducing a strong fragmentation of the E1 nuclear response below the neutron binding energy. |
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Address |
[Avigo, R.; Wieland, O.; Bracco, A.; Camera, F.; Benzoni, G.; Blasi, N.; Bottoni, S.; Brambilla, S.; Crespi, F. C. L.; Leoni, S.; Million, B.; Morales, A., I; Pullia, A.; Riboldi, S.] Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy, Email: oliver.wieland@mi.infn.it |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000612225400080 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4700 |
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Permanent link to this record |
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Author |
AGATA Collaboration (Cederwall, B. et al); Gadea, A.; Jurado, M.; Domingo-Pardo, C.; Huyuk, T.; Perez-Vidal, R.M. |
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Title |
Isospin Properties of Nuclear Pair Correlations from the Level Structure of the Self-Conjugate Nucleus Ru-88 |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
124 |
Issue |
6 |
Pages |
062501 - 6pp |
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Keywords |
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Abstract |
The low-lying energy spectrum of the extremely neutron-deficient self-conjugate (N = Z) nuclide Ru-88(44)44 has been measured using the combination of the Advanced Gamma Tracking Array (AGATA) spectrometer, the NEDA and Neutron Wall neutron detector arrays, and the DIAMANT charged particle detector array. Excited states in Ru-88 were populated via the Fe-54(Ar-36, 2n gamma)Ru-88* fusion-evaporation reaction at the Grand Accelerateur National d'Ions Lourds (GANIL) accelerator complex. The observed gamma-ray cascade is assigned to Ru-88 using clean prompt gamma-gamma-2-neutron coincidences in anticoincidence with the detection of charged particles, confirming and extending the previously assigned sequence of low-lying excited states. It is consistent with a moderately deformed rotating system exhibiting a band crossing at a rotational frequency that is significantly higher than standard theoretical predictions with isovector pairing, as well as observations in neighboring N > Z nuclides. The direct observation of such a “delayed” rotational alignment in a deformed N = Z nucleus is in agreement with theoretical predictions related to the presence of strong isoscalar neutron-proton pair correlations. |
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Address |
[Cederwall, B.; Liu, X.; Aktas, O.; Ertoprak, A.; Zhang, W.; Qi, C.; Nyberg, A. Atac; Back, T.; Doncel, M.; Gottardo, A.] KTH Royal Inst Technol, S-10691 Stockholm, Sweden, Email: cederwall@nuclear.kth.se |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9007 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000513242500002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4278 |
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Permanent link to this record |
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Author |
AGATA collaboration (Collado, J. et al); Civera, J.V.; Gadea, A. |
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Title |
AGATA phase 2 advancements in front-end electronics |
Type |
Journal Article |
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Year |
2023 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
59 |
Issue |
6 |
Pages |
133 - 20pp |
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Keywords |
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Abstract |
The AGATA collaboration has a long-standing leadership in the development of front-end electronics for high resolution ?-ray spectroscopy using large volume high purity germanium detectors. For two decades, the AGATA collaboration has been developing state-of-the-art digital electronics processing with high resolution sampling ADC, high-speed signal transfer and fast readout to a high throughput computing (HTC) farm for on-line pulse shape analysis. The collaboration is presently addressing the next challenge of equipping a 4p array with more than 6000 channels in high resolution mode, generating approximately 10 MHz of total trigger requests, coupled to a large variety of complementary instruments. A next generation of front-end electronics, presently under design, is based on industrial products (System on Module FPGA's), has higher integration and lower power consumption. In this contribution, the conceptual design of the new electronics is presented. The results of the very first tests of the pre-production electronics are presented as well as future perspectives. |
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Address |
[Collado, J.; Gonzalez, V.] Univ Valencia, Dept Ingn Elect, Valencia 46100, Spain, Email: gadea@ific.uv.es |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6001 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001015065300001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5567 |
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Permanent link to this record |